The present invention relates generally to devices for displaying information or images and, particularly, to a device for producing an optical illusion of displayed information or images utilizing the phenomenon of light persistence of an eye and time and/or position division multiplexing techniques.
A variety of devices and/or methods exist for displaying information or images. Such devices and/or methods include liquid crystal displays (LCDs); plasma and fluorescent gas discharge screens; electro-luminescent displays; light emitting diodes (LEDs); cathode ray tubes (CRTs); and projection devices such as laser scanners and light valve projectors. Other devices include signs formed of incandescent lamp matrices and large area liquid crystal polymeric dispersion thin films.
These devices and/or methods suffer from certain drawbacks. Display devices such as liquid crystal displays have a limited viewing angle and a low contrast ratio between the displayed image and background. Gas discharge devices and electro-luminescent displays require very intricate and complex matrices. LED displays generally require high power consumption matrices and CRTs are bulky and require high supply and driving voltages. Projection devices are also bulky and have a limited resolution. Large area liquid crystal polymeric thin films have a limited temperature range and a low contrast ratio.
Another drawback common to such devices and/or methods is that information or images are generally presented on planar displays. As such, true three-dimensional presentation of images is limited.
U.S. Pat. No. 4,099,172 to Montanari et al. discloses an electronic visual display for alphanumeric characters. The display utilizes at least one LED to create at least one dot matrix for alphanumeric characters. A rotating prism made of a transparent material and having a hexagonal cross-section is interposed between the LED and an observer. In consequence of the rotation of the prism and of the different inclination of its faces, a virtual image of the LED is successively positioned at all of the points of a matrix of 5 columns. Turning on and off of the LED is synchronized with the rotation of the prism by means of a sensing device cooperating with a strobe wheel. The emitted light is modulated according to the desired character so that for each LED utilized, a full alphanumeric character is displayed.
U.S. Pat. No. 4,298,868 to Spurgeon discloses an electronic display apparatus that produces an optical illusion of various combinations of circular patterns such as circles or leaves with rounded end points. An array of LEDs mounted on the plane of a rotating disk is selectively activated to control the geometric patterns formed. The LEDs are driven by demodulators that convert an analog signal, the signal that selects the pattern to be formed, to a digital signal, the signal that drives the LEDs. The LEDs are driven without regard to the rotational position of the disk. Additionally, the images generated are presented in a planar format.
U.S. Pat. No. 4,383,244 to Knsuff discloses a multi-light display device wherein intensified LEDs are intermittently energized while in rotary motion. Use is made of the phenomenon of light persistence of an eye so that dots and bars are selectively perceived by an observer.